The ATP-dependent generation of membrane potential by sub-bacterial vesicles from the marine bacterium, Vibrio alginolyticus

AbstractAddition of ATP leads to the accumulation of the permeant anion PCB− by sub-bacterial vesicles from Vibrio alginolyticus. This accumulation is caused by Δψ generation by ATPase, the effect being inhibited by CCCP, gramicidin D and DCCD. Δψ values may be increased by incubation of sub-bacterial vesicles at room temperature and with the protein fraction isolated according to Beechey et al. [(1975) Biochem. J. 148, 533–537] from another portion of the sub-bacterial vesicles. Δψ generation is observable only in the presence of Mg2+ at high concentrations (optimum ≈ 30 mM). Proceeding from experimental data we assume that Mg2+ reduces passive H+ conductivity of the vesicle membranes. Thus, a Δψ-generating ATPase has been shown for the first time in V. alginolyticus membranes